Wireless-telephone receiving apparatus



June 17 1924. 1,498,129

A. E. SPICER WIRELESS TELEPHONE RECEIVING APPARATUS Filed June s, 1925 1Z6 10 P 29' 5 17 55 F i 1 5 z i (J? I 40; T 5 31 Z6 5 52 E 9 4L a 68 Patented June 17, 19 24.

UNITED STATES 1,498,129 PATENT OT'FFTCE.

ARTHUR n srrcnn, or NEW YORK, N. Y., ass mno n, BY manor annunsnn AS- smmlENTs, To THOMAS J. r. 'COADY, TRUSTEE, or NEW YORK, N. Y.

Application filed June 5,

To all whom it may concern:

Be it known that I, ARTHUR E. SPIoER, a citizen of the United States, residing at New York, in the county of Kings and State 5 of New York, have invented certain new and useful Improvements in Wireless-Tele phone Receiving Apparatus; and I do herey declare the 0 and exact description 0' the invention, such as will enable others skilled in the art to which it appertains to lnakeand use the same.

My invention consists in the novel features hereinafter described, reference being 1. had to the accompanying drawing, which shows one embodiment of the same, selected by me for urposes of illustration, and the said inventlon is fully disclosed in the following description and claims.

My invention consists in a novel receiving apparatus for wireless telephony, whereby the use of an outdoor antenna or aerial may be dispensed with, and whereby interference from spark or wireless telegraphy transmitters, can be readily prevented,'and which will at the same time be very sharp in tuning and will render the selected signals, whether speech or music in a very clear and satisfactory manner, free from exterior noises. In carrying in invention into efiect, I employ a coil whic I term a miniature loop or primary coil, and which consists of a plurality of single turns wound around a ho low body, as a c linder of insulating material, the ends of the coil being shunted preferably through two condensers, and the coil being rovided with a single tap located substantial y midway the length of the coil. In connection with this coil, I employ two rotors, also preferably of cylindrical structure, upon each of which is wound a plurality of sin le turns, one of these. rotors being locate adjacent to each end-of'the miniature loop or primary coil. One of the rotor coils is connected in series in the grid circuit of a three-element audion tube, and is connected to the shunt circuit of the prima coil, substantiall midway between the con ensers therein. he other rotor coil is connected in series in the ground circuit extending from the before mentioned tap of the primary coil through a condenser to the rotor coil, and thence to ground. In connection with this apparatus, I also employ llowin to be a full, clear,

1928. Serial No. 643,497.

a variable condenser in a shunt circuit,-connecting the grid circuit with the filament circuit of the audion tube, and in some instances I also employ an additionalcondenser in a shunt circuit from the grid circuit to the ground circuit between the second rotor coil and ground. The other features of the circuit in which my improved apparatus is employed, may be of any usual or preferred type, and for t e urpose of making the received signals on er, one or more stages of audio amplification may be employed in the usual manner.

Referring to the accompanying drawings,

Fig. 1 is a diagram representing the circuit, includin the usual detector audion tube and usua telephone receiver;

Fig. 2 is a top plan View partly in section, of my improved primary coil or miniature loop with rotors and condensers connected therewith.

Fig. 3 is an end elevation of the same.

Fig. 4' is a detail showing the contact rings and brushes for one of the rotor coils.

Referring to the drawings, 1, represents my improved miniature loop or primary coil,'consisting of a cylinder, 2, of insulating material, such as bakelite or the like, upon which is Wound a coil proper comprising a plurality of singleturns having a single tap, indicated at 3, located substantially centrally with respect to the length of the coil. The turns of the coil occupy the major portion of the tube, 2, leaving plain or uncovered end portions at either end of the coil within which are located the 'two rotors, which, for convenience of reference I term the main rotor, which is in the grid circuit, and the auxiliary rotor, which is in the ground circuit. The main rotor consists of a short cylinder, 4, of insulating material, upon which is wound in single turns, the main rotor coil, 5. The end wires of the coil, indicated at 5-5", are preferably soiarran ed as not-to interfere with the rotation o the rotor. This may be accomplished in a number of ways. In the present instance I have shown the rotor mounted upon a hollow shaft, 6, of insulating material, such as bakelite tubing, which is mounted in bearing a ertfires arranged diametrically opposite eac other in the end portion of the tube, 2. The end wires, (9-5, of the main rotor coil, 5, are in this the outer ring, 8.

1 .-:mits the rotor to be turned without interinstancepassed through an aperture in the 'fering with its connections in the circuit, but it is to be understood that any other suitable arrangement which will permit the rotation of the rotor may be employed. In some instances the terminal wires of the rotor coil may be simply brought out through the hollow shaft, 6, and directly connected, but in such case, it would be necessary to provide a stop, or stops, to limit the'rotation of the shaft to prevent twisting up the lead wires, and I therefore prefer the construction herein shown and described, or its equivalent construction, which does not interfere with the rotation of the rotor in any way.

At the opposite end of the tube, 2, is located the auxiliary rotor, which is constructed and arranged in precisely the same manner as hereinbefore described with respect to the main rotor, and it comprises the cylinder, 11, of insulating material, upon which is wound the auxiliary rotor coil, 12, the end. wires, 12--12", of which are brought out through the hollow shaft, 13, of insulated material and connected respectively to .the brushes, 1415, which respectively engage insulated concentric contact plates, le -15, to which are connected the wires, 16'17. respectively. For convenience in attaching the ground circuit from the wire, 31, hereinafter referred to, to the wire, 17, the latter may be connected to a binding post, indicated at 17, in Fig. 3, secured to the tube, 2, and in like manner,

the lead wire, 10, from the other rotor may be conveniently connected with a similar binding post (not shown) if desired. Each of the rotor shafts, 6 and 13, is provided with means for rotating the same which is preferably the customary dial, one, of whichis indicated at 18, in Fig. 3. I

The main primary coil or miniature loop is provided, as before stated, with a shunt circuit preferably through two condensers. In Fig. 2. I have shown these two condensers at 19 and 20, mounted b means of screws or otherwise, upon the lnsulating tube, 2, the end wires, 1 and 1",,respectively, of the coil, 1, being connected, the one to the condenser 19, and the other to the condenser,

20, and the two condensers being connected by a shunt wire. 21, to the center of which, midway between the two condensers, 19-20, is connected the wire, 9, leading to the inner ringfl', of the main rotor, and connecting with the end of the coil, 5, nearest the primary coil. The central tap, 3, of the primary coil or miniature loop, is connected to the end of the auxiliary rotor coil nearest the primary coil, through a condenser, as before stated. In the drawings, this connection is illustrated by the wire, 22, which extends from the tap, 3, to the condenser. 23, also conveniently mounted on the tube, 2, the other contact of the condenser being connected by wire, 24, to the contact plate, 14 thus insuring its connection through the brush, 14, and terminal wire, 12*, with the auxiliary rotor coil, 12. For convenience of reference I term the ends of the rotor coils which are nearer to the primary coil when the-rotors are in the position shown in Fig.2 as the inner ends of said coil. They are the lower ends, as shown in the diagram in Fig. 1. The condenser-s, 19, 20 and 23, illustrated in Fig. 2, and before referred to, are preferably condensers of fixed capacity constructed in the usual manner, although I do not wish to limit myself to any articular type of condenser, and obviousy variable condensers could be employed if it was so desired.

InFig. 1 I have illustrated diagrammatically one arrangement of my improved wireless telephone receiver which has been found to be extremely advantageous and efficient. In connecting the apparatus before described in a receiving circuit, I employ the usual three-element audion detector tube, which is illustrated diagrammatically, and in which, F, represents the filament, G, the grid, and P, the plate. The filament is connected in circuit by wires, 2526, with the usual battery, indicated at A, and is provided with the usual rheostat, indicated at 27, of any desired type. The grid of the detector, G, is connected to t wire, 10, at the outer end of the main roto by means of a wire, 28, and the usual grid condenser, 29, and grid-leak, 30 are employed in connection with the grid. The wire, 17, at the outer end of the auxiliary rotor is connected by a ground wire, 31, with ground, in any desired manner, ordinaril by connecting it to a pi e forming part 0 the water system of the uilding, 1n which the receiving apparatus is employed. The wire, 9, connectmg the shunt circuit of the primary coil with the inner end of the main rotor is also connected to the minus side of the battery, A, by a wire, 32. A. variable condenser, preferably of the 43-plate type, indicated at 33, is employed in a shunt wire, 34, connecting the grid circuit with the filament circult. In some instances I have found it desirable also to employ an additional fixed condenser, 35, in a shunt, 36, from the grid circuit wire, 28, to the round wire, 31, as shown in Fig. 1, but t'is additional condenser is not essential and may bepmitted. The plate circuit is of the usual type and consists of the wire, 37, leading from the plate to the telephone receiver, indicated at T, thence by wire, 38, to the platecircuit battery, B, the minus side of which is connected through a potentiometer, 39, with the, A, battery in a well known manner. The potentiometer is not essential, however, and may be omitted. I have also indicated a fixed condenser, 40, in a shunt wire, 41, across the telephone apparatus from the wire, 37, to the wire, 38, which is usually in such receivers, although in some instances it may be omitted.

The receiving apparatus is tuned by rotatin the main and auxiliary rotors, and the varia le condenser, 33. No aerial or antenna is required. When the adjustment of the rotors and variable condenser, 33, has

'been made in such manner as to bring in the signal fromthe broadcasting station, in the strongest and clearest possible manner, should any interference from other broadcasting stations or from spark or telegraph transmitters be audible at any time Whilethe receiver is in use, these extraneous sounds can be practically eliminated by a proper adjustment of the auxiliary rotor in'one direction or the other. It is also found that in the use of my improved receiving apparatus the influence of staticis practically eliminated.

It is my understanding that the main coil or-min'iature loop, 1, forms a loop for the reception of broadcasting waves, and that the receiver is tuned to the proper wave length by the adjustment of the main rotor coil, 5, and the variable condenser, 33, and that the portion of the main coil, 1, between the loop and the terminal, 1 in conjunction with the auxiliary rotor, 12, and the condenser, 20, acts as a choke coil to eliminate spark or telegraph signals, and other extraneous noises durin the reception of broadcasting signals. wish it to be understood, however, that my invention resides in the apparatus herein shown and described, and which has proved highly eficient in actual operation, regardless of the theory upon which it operates.

It will be understood'that the signals received by this apparatus can be readily am-. plified 1n the usual and well understood manner, b inserting in the wires, 37 and 38, an audio t i'equency transformer and an amplifyin audion tube, so that the signals will be amp ified before reaching the telephonereceiver, T, and it will also be understood that any number of stages of audio amplification may be employed, and that the telephone apparatus, indicated at, T, in Fig. 1, may be either a head phone, loud speaker or othertype of telephone apparatus.

What I claim and desire to secure by Letters Patent is 1. In a wireless telephone receiving apparatus, a tuning unit, comprising a primar coil having a tap substantially central y of the length of the coil, and having the ends of the coil connected by a shunt circuit, a rotor coil located adjacent to each end of said primary coil, one of said rotor coils' being connected to the primary coil,

and the other rotor coil being connected with thc's'aid tap and'a ground connection.

2. In a Wireless telephone receiving apparatus, a tuning unit, comprising a primary coil having a tap substantially centrally of the length of thecoil, and having the ends of the coil shunted through two condensers, a rotor coil located adjacent to each end of said primary coil, one of said rotor coils'being connected at one end to the primary coil between said condensers, and at the other end to the grid of a three-element audion tube, and the other rotor cp'il being connected between the said'tap and a ground connection, and a condenser in said ground connection.

3. In a Wireless telephone receiving apparatus, a tuning unit comprising a primary coil having a plurality of single turns, provided with a tap located substantially centrally, and having its ends shunted through two condensers, a rotor coil mounted adjacent to each end of the primary coil, a connection from the inner end of One of said rotor coils to the said shunt connection, between the condensers therein, the other end of said rotor coil being connected to the grid of a three-element audion tube, the inner end of the other rotor coilbeing connected with the said primary coil tap through a condenser, and the outer end of said rotor coil having a ground connection.

4. In a wireless telephone receiving apparatus, the combination with a primary coil, provided with a tap substantially central of the length of the coil, and having the ends of the coil shunted through two condensers, of a rotor coil adjacent to each end of the primary coil, one of said rotor coils being connected in series in the grid circuit of a three element audion tube, and

connected to the primary coil between said condensers, and the other rotor coil having a ground connection and. being connected.

between said primary coil tap and ground connection.

5. In a wireless telephone receiving apparatus, the combination with a primary coil, provided with a tap substantially central of the length of the coil, and having the ends of the coil shunted through two condensers, of a rotor coil adjacent to each end of the primary coil, one of said rotor coils being connected in series in the grid circuit of a three element audion tube, and connected to the primary coil between said condensers, and the other rotor coil having a ground connection and being connected between said primary coil tap and ground connection, and a condenser between said tap and the said second rotor coil.

6. In a wireless telephone receiving apparatus, the combination with a" primary coil, provided with a tap substantially central of the length of the coil, and having the ends of the coil shunted through two condensers, of a rotor coil adjacent to each end of the primary coil, one of said rotor coils being connected in series in the grid circuit of a three elementaudion tube, and connected to the primary coil between said condensers, and the other rotor coil having a ground connection and being connected between said primary coil tap and ground connection, a filament circuit, a plate circuit including a telephone receiver, and a variable condenser inserted across the grid and filament circuits.

7. In a wireless telephone receiving apparatus, the combination with a primary coil, provided with a tap substantially central of the length of the coil, and having the ends of the coil shunted through two condensers, of a rotor coil adjacent to each end of the primary coil, one of said rotor coils being connected in series in the grid circuit of a three element audion tube, and

connected to the primary coil between said condensers, and the other rotor coil havin a ground connection and being connecte between said primary coil tap and ground connection, a filament circuit, a plate circuit including a telephone receiver, and a variable condenser inserted across the grid and filament circuits, and a condenser interposed between the primary coil tap and said ounded rotor.

8. n a wireless telephone receiving apparatus, the combination with a primary coil, provided with atap substantially central of the length of the coil, and having the ends of the coil shunted through two condensers, of a rotor coil adjacent to each end of the primary coil, one of said rotor coils being connected in series in the grid circuit of a three element audion tube, and connected to the primary coil between said condensers, and the other rotor coil having a ground connection and being connected between said primary coil tap and ground connection, a filament circuit, a plate circuit including a telephone receiver, and a variable condenser inserted across the grid and filament circuits, a fixed condenser interposed between the primary coil ta and said grounded rotor, and a fixed con enser across the grid circuit and the ground cir+ cuit.

In testimony whereof I aflix in Si ature.

ARTHUR E. P GER.

Witness:

J. FREDERICK CRYER. 

